Pneumatic brake setting means with emergency mechanical actuator therefor



Dec. 13, 1966 B. E. STEVENSON ET AL PNEUMATIC BRAKE SETTING MEANS WITHEMERGENC MECHANICAL ACTUATOR THEREFOR Original Filed June 24, 1963 Pics.

INVENTORS. BILLY E. W50" BY JOHN T. OSTGAARD My p242 a ATTORNEYS.

United States Patent Continuation of application Ser. No. 289,966, June24,

1963. This application Apr. 6, 1965, Ser. No. 448,558 2 Claims. (Cl.9263) This application is a continuation of our application for UnitedStates Letters Patent Ser. No. 289,966, filed June 24, 1963, entitledPneumatic Brake Setting Means, now abandoned.

This invention relates generally to pneumatic braking systems such asused on trucks and trailers and more particularly to an improvedpneumatic brake setting means incorporating emergency fail-safe typemechanical brake setting means.

In copending patent application Ser. No. 97,368, filed Mar. 21, 1961,and entitled Fluid Operating Braking System, there is disclosed apneumatic braking system which includes a mechanically powered alternatebrake setting means. In the preferred embodiment of this alternate brakesetting means the normal pneumatic system for operating the brakestogether with the alternate brake setting means is incorporated in asingle casing structure. This casing structure is disposed adjacent tothe brake drums on the vehicle or trailer, as the case may be, tooperate the brake shoes.

As shown and described in the aforementioned copending application, thecasing includes a typical brake booster having an actuating rod meansfor coupling the same to the brake mechanism. This booster incorporatesa heavy-duty diaphragm for actuating the rod means in response topressurized air received on one side of the diaphragm. The rod means isresiliently positioned against the opposite side of the diaphragm sothat when the diaphragm is moved in response to pressurized air, the rodmeans will actuate the brake drums. When the pressurized air isexhausted the rod means will release the brakes.

The casing also includes a second or emergency chamber disposed to therear of the booster. This second chamber incorporates a secondheavy-duty diaphragm to the rear of which there is disposed powerfulspring means. A rigid force transmitting member, in turn, is disposedbetween the first and second diaphragms such that when the powerfulspring means is released, this force transmitting member will urge thefirst diaphragm forwardly and thus actuate the rod means to set thebrakes. The powerful spring means will only be released to set thebrakes in the event of loss of air pressure in the forward portion ofthe second chamber.

In order that a vehicle may be moved after loss of air pressure, such asmight result from a leak in the pneumatic line or failure of thecompressor to operate, it is desirable to provide means for mechanicallyretracting the powerful spring means to release the brakes therebypermitting movement of the vehicle. In the copending applicationreferred to, such a mechanical lockout means is incorporated as a partof the casing structure and extends from the rear of the casingstructure normally. Thus, the overall length of the casing structure isincreased rendering it awkward to mount the casing and subjecting theexposed part of the lockout to the elements and various hazards.Further, the powerful spring means themselves require, in the particulardesign disclosed, a relatively long operating space, again increasingthe overall length of the casing structure.

With the foregoing considerations in mind, it is a primary object ofthis invention to provide an improved and simplified pneumatic brakesetting means in combination with emergency brake setting means, allhoused within a single casing unit of minimum overall lengthconsiderably shorter than has been required heretofore, and yet fromwhich the same advantages may be realized.

More particularly, it is an object to provide a pneumatic brakeactuating and setting means which includes mechanical means forreleasing the brakes in the event of failure of pressurized air and yetin which the provision of such mechanical means does not increase theoverall length of the casing structure.

Another important object is to provide an improved pneumaticallyoperated brake setting means incorporating powerful spring means of aunique design when considered in the overall combination for againenabling minimization of the overall length of the casing structurewithout sacrificing the required strength of the powerful springsemployed and featuring a floating inner end free of connection to thediaphragm and of guide support from stationary components of theassembly.

Briefly, these and many other objects and advantages of this inventionare attained by providing a casing struc ture having a rod actuatingmeans extending from one end adapted to be coupled to the brakemechanism of the vehicle. The casing structure itself includes a firstchamber incorporating a first heavy-duty diaphragm which is responsiveto pressurized air to extend the rod means and thus set the brakes.Similarly, exhaust or relieving of this pressurized air will permit therod means to retract within the first chamber and thus release thebrakes.

The same casing unit also includes a second chamber disposed to the rearof the first chamber and having a common wall therewith provided with anopening. This second chamber incorporates a second heavy-duty diaphragm.A rigid force transmitting member has one end passing through theopening in the common wall to bear against the rear surface of the firstdiaphragm and its other end in engagement with the front surface of thesecond diaphragm in the second chamber. Powerful spring means preferablyof barrel configuration are disposed to the rear of the second diaphragmto urge the second diaphragm towards the first diaphragm. Means areprovided for providing pressurized air to the front portion of thesecond chamber to hold the powerful spring means in a compressed state.

In the event of loss of pressurized air resulting in the powerful springmeans setting the brakes through the medium of the rigid forcetransmitting member, the desired mechanical lockout means for retractingthe spring takes the form of a threaded stud and nut normally carriedcaptively on the side of the casing to avoid increasing the overalllength of the casing. The rear portion of the second chamber housing thepowerful spring means, in turn, includes a unique annular platestructure disposed between the floating inner end of the powerfulsprings and the rear surface of the second heavy-duty diaphragm againstwhich the powerful spring means acts. This plate is provided withfast-action disconnect means adapted to be engaged by one end of thethreaded lockout stud when the threaded stud is received within a rearaccess opening in the second chamber. The threaded stud and anassociated nut may then be employed to retract the powerful springmeans. When not in use, the stud and nut are simply replaced in theprotective carrying portion on the side of the casing structure. Thisunique provision of the mechanical lockout means coupled with the use ofthe barrel type helical coil spring for the powerful spring meanswherein the end coils will fit within the center coils when the springis compressed enables the overall length of the casing to be minimizedwithout sacrificing the effectiveness of the structure in setting andreleasing the brakes.

A better understanding of the invention will be had by now referring toa preferred embodiment thereof as illustrated in the accompanyingdrawings, in which:

FIGURE 1 is an overall perspective view of the improved pneumatic brakesetting means of this invention;

FIGURE 2 is a cross-section taken generally in the direction of thearrows 2-2 of FIGURE 1, illustrating the relative positions ofcomponents when the brakes are in released condition; and

FIGURE 3 is another cross-section similar to FIGURE 2, but illustratingthe relative positions of the components when the brakes are partiallyset.

Referring first to FIGURE 1, the brake setting means includes a casingstructure having a front cup-shaped casing section 10, an intermediatesection 11, and a rear cupshaped casing section 12, it being pointed outthat housing sections 11 and 12 take the place of the usual end cap ofthe brake booster housing 10.

The three sections are held together by encircling clamps or bands 13and 14. As shown, there is provided a brake setting actuating rod means15 protruding from the front portion of the casing and terminating in ayoke structure 16 adapted to be directly coupled to the cam mechanismfor operating the brake drums of the vehicle. The arrangement is suchthat forward extended movement of the rod means 15 from the casingstructure serves to actuate or set the brakes and retracting movement ofthe rod means 15 will release the brakes.

In accordance with a feature of this invention, the casing structure isprovided on one side with a pocket 17 arranged to receive a threadedstud 18 having a nut 19 threaded to its lower end to hold the studwithin the pocket 17. The upper portion of the stud includes laterallyextending projections 20 constituting an engaging means, the purpose forwhich will become clearer as the description proceeds. As indicated bythe dotted lines in FIGURE 1, the stud l8 and nut 19 may be easilyremoved from the pocket 17 by simply unthreading the nut and lifting thestud upwardly as shown at 18.

Also illustrated in FIGURE 1 are suitable mounting lugs 21 and 22 forthe casing structure to enable mounting the same adjacent to the brakedrums of the vehicle. Suitable air pressure inlet and exhaust lines,such as indicated at 23 and 24 are provided to enable pneumaticoperation of the mechanism within the casing. As indicated in FIGURE 1,the overall length of the casing structure is indicated at d and, inaccordance with an important feature of this invention, this overalllength is maintained at a minimum value.

Referring now to FIGURE 2, the front portion of the casing structureitself includes a first chamber 25 incorporating a first or boosterheavy-duty diaphragm 26, the peripheral edges of which may be clampedbetween the casing sections and 11 by means of the clamping ring 13. Therod means in turn terminates in an annular plate 27 resiliently heldagainst the front face of the diaphragm 26 as by a spring 28. Means areprovided in the form of the opening 29 from which the rod means 15extends to vent the front portion of chamber 25 to atmosphere. Theportion of the chamber to the rear of the diaphragm 26 in turn isarranged to receive pressurized air from the line 23 of FIGURE 1 througha suitable inlet port 23, as shown in FIGURE 2.

With the arrangement described thus far, the spring 28 will normallyhold the plate 27 and diaphragm 26 in their extreme right hand orrearward positions so that the rod means 15 is retracted and the brakesof the vehicle are released. When it is desired to operate the brakes,pressurized air is received through the port 23' to the rear of thediaphragm 26, thus urging the diaphragm forwardly to extend the rodmeans 15 and actuate the brake drum. Release of the brakes is effectedby simply exhausting air through the same port 23' or a suitable exhaustport (not shown).

The alternate emergency brake setting portion incorporated within thecasing structure is shown to the right of the first chamber 25. Thislatter emergency mechanism includes a chamber 30 disposed to the rear ofthe chamber 25 and having a common wall portion therewith defined by thecenter casing section 11. As shown, this common wall portion 11 includesan opening 31. Vlithin the second chamber 30 there is incorporated asecond heavyduty diaphragm 32. A rigid force transmitting member 33 inturn passes in sealing relationship through the opening 31 to bearagainst the rear surface of the first heavy-duty diaphragm 26, and hasits other end resiliently bearing against a plate 34 in engagement withthe front surface of the second heavy-duty diaphragm 32. The resilientengagement is effected by a spring 35 in the front portion of the secondchamber 30. The front portion of the chamber 30 is adapted to receivepressurized air through an inlet port 24' which communicates with theinlet line 24 described in FIGURE 1. Thus, by admitting pressurized airto the second chamber 30, the second diaphragm 32 will be urgedrearwardly to the right as shown.

Housed within casing 12 is a powerful coil spring 38 preferably ofbarrel configuration, as is best shown in FIG- URE 3. It will beunderstood that the diameters of adjacent convolutions preferably differsufficiently for nesting of the end convolutions within the largermidsection convolutions in the manner best shown in FIGURE 2, this beingin the interest of maximum compactness and lightness without sacrificein performance characteristics. Of importance too is the fact that theinner end of spring 38 is fioatingly supported without need for aid fromguide means heretofore customarily employed. In other words, the outerend of the spring nests over a boss or the like projecting inwardly fromthe end wall of casing 12 and the inner spring end nests overcomplementally shaped boss means centrally of the bearing plate 36. Thespring is so dimensioned that its largest convolution is smaller indiameter than the internal diameter of casing 12 and does not bindthereagainst when fully compressed, as is evident from FIGURE 2.However, the lower outer surface of the largest convolution may havesliding contact with the inner lower side wall of casing 12 forself-evident reasons, and cooperates therewith in floatingly supportingthe inner end of the spring and plate 36 against the center of diaphragm32.

Owing to the described floating mode of supporting plate 36, it will beunderstood that there is no opportunity for the described emergencycomponents, namely, plate 36 and spring 38, to become twisted or to bindagainst any other component. Malfunctions from these sources aretherefore completely avoided. Likewise, there are no close manufacturingtolerances to be observed and checked during manufacture and assembly.Additionally, temperature changes cannot affect the operation nor canthe components under consideration become fouled with dirt and foreignmatter.

It will be understood that bearing plate 36, as shown, includes atubular boss centrally thereof provided with a pair of notches 37 alongdiametrically opposed portions of its inner side wall forming the femaleportion of bayonet mounting means. action coupling for lockout device18, the inner end of which carries a pin 20 forming the male part of thebayonet mounting, as coupling, well known in the coupling art. As hasbeen pointed out, the shank of lockout member 18 is threaded andprojects loosely through the vent and access opening 39 axially 0f theend wall of easing 12. This opening is normally closed as by the plasticplug 40.

With reference now to both FIGURES 2 and 3, the operation of thepneumatic brake setting structure will be set forth. As describedheretofore, assuming that pressurized air is maintained in the frontportion of the charm This means is part of a fastber 30, the powerfulspring means 38 and diaphragm 32 will remain in the positionsillustrated in FIGURE 2. Since the front portion of the rigid forcetransmitting means 33 engaging the rear of the first diahragm 26 is notsecured to the diaphragm 26, the diaphragm 26 and rod means are free tomove to extended or retracted positions independently of the rigid forcetransmitting member 33. Thus, the normal pneumatic operation of thebrakes may be carried out.

When it is desired to set the brakes as for parking or in the event thatthe pressurized air system fails, the decreased pressure within thesecond chamber resulting from exhausting the air therefrom or from afailure in the pressure line will enable the powerful spring means 38 tourge the second diaphragm 32 towards the left, thus moving the rigidforce transmitting member 33 through the opening 31 to, in turn, pushthe first diaphragm 26 and rod means 15 from the end of the casing. Thisaction is illustrated in FIGURE 3 wherein the rod means 15 has beenpartially extended from the front end of the casing.

In order for the driver to release the brakes when they are set in thisemergency condition, he need only apply pressurized air through theinlet port 24" to bear against the front surface of the second diaphragm32 and compress the powerful springs 33. However, in the event of lossof pressurized air due to the mechanical failure in the compressor or aleak in the hydraulic or pneumatic lines, the mechanical brake releasingmeans described in conjunction with FIGURE 1 in the form of the stud 18and nut 19 may be used. Thus, the small plastic plug cap 40 is removedand the stud 18 remove-d from the pocket 17 and inserted into the accessopening 39 as illustrated in FIGURE 3. The engaging projections 20 onthe end of the stud 13 are then hooked into the hook portion 37 of theplate 36 and the nut 19 then threaded on the opposite protruding end ofthe stud. The diameter of the nut is larger than the access opening sothat continued threading of the nut onto the stud will draw the plate 36to the right thereby compressing the powerful spring 33. Compression ofthe spring 33 enables the force transmiting member 33 to be retracted bythe spring 35 and thus enables the retraction of the rod means 15.

When pressurized air has been restored to the system, the diaphragm 32will serve to hold the springs 38 compressed so that the stud 18 maythen readily be disengaged and removed from the access opening 39. Theplastic plug 40 is inserted in the access opening and the stud and nutare then replaced within the pocket structure 17 of FIGURE 1.

It will be noted from the foregoing description that the mechanicalcompressing of the powerful springs 38 can readily be effected withoutthe necessity of providing permanent mechanical compressing means on therear portion of the casing. Thus, the feature of mounting the mechanicalspring compressing means on the side of the casing enables the overalllength of the casing to be materially decreased. The length of thecasing is only increased when the stud and nut are actually in use.

In addition to the foregoing, it will be noted that the powerful springmeans 38 is in the form of a helical coil spring of barrelconfiguration. With this design, the end coils of the spring may fitwithin the center coils, as illustrated in FIGURE 2, when the spring isin compressed condition, thereby again enabling the overall length ofthe casing structure to be considerably shortened.

From the foregoing description, it will thus be evident that the presentinvention has provided a greatly improved pneumatically operated brakesetting means with emergency mechanical actuator therefor. While onlythe one particular embodiment has been set forth for purposes ofillustration, various minor changes that fall clearly within the scopeand spirit of this invention will occur to those skilled in the art. Thebrake setting structure is therefore not to be thought of as limited tothe exact embodiment set forth merely of illustrative purposes.

\ Ve claim:

1. In combination with a brake operating booster, means for operatingsaid booster mechanically comprising a housing attached to the booster,means therein including an operating connection to said booster tooperate the latter upon failure of the normal operating means therefor,said last-mentioned means including a generally flat, imperforateflexible diaphragm, powerful coil spring means having one end seatedagainst the interior wall of said housing and a bearing plate floatinglysupported against the diaphragm by said spring means, said bearing platebeing constructed and defined with temporary holding means for acceptinga spring lockout tool when substantially aligned with the axis of thespring and facing toward the housing wall seating said spring end, saidhousing having an opening aligned with the axis of said spring and thetemporary holding means for the bearing plate, a spring lockout tool forextending through said opening for engagement with the temporary holdingmeans to allow the lockout tool to be 0perated for compressing thelocking out the spring mechanically when the spring is either in acompressed or an expanded condition, a removable cap for said housingopening to seal off the interior of the housing when the lockout tool isdisengaged from the temporary holding means and withdrawn from thehousing, said lockout tool comprising a threaded shank insertablethrough said housing opening and having one end thereof constructed anddefined to detachably interlock with the temporary holding means, saidthreaded shank having nut means on its other end engageable with theexterior of said housing and cooperating therewith as the nut means istightened to compress said spring, said housing is provided with a toolstorage pocket for receiving and storing the major portion of thelockout tool for protecting same from its environment to therebymaintain the tool in a convenient and readily accessible location in ausea ble condition when the spring is required to be locked out, saidtool being tightly secured to the pocket to prevent loss of same duringoperation of the associated vehicle by the nut being tightened to thepocket and released from the pocket by untightening the nut andwithdrawing the tool from the pocket.

2. In a combination as defined in claim 1 wherein the detachableinterlock for said lockout tool comprises a pin extending transverselyof the threaded shank for coaction with said temporary holding means toallow for quick engagement and disengagement with the temporary holdingmeans through rotation of the tool in one direction to cause the pin tobe held by said temporary holding means and rotated in the oppositedirection to be released therefrom, and wherein said bearing plate has aboss defined substantially centrally thereof having the temporaryholding means constructed and defined on the boss to accept the crosspin and hold same upon rotation of the shank to seat the cross pinthereagainst and to release same upon rotation in the oppositedirection.

References Cited by the Examiner UNITED STATES PATENTS 1,429,024 9/1922Douglass 254-10.5 2,976,085 3/1961 Grogan 92-63 3,107,583 1'0/1963Woodward 9263 3,109,347 11/1963 Brodl et al. 92-128 3,112,959 12/1963Kateley 92-128 3,152,521 10/1964 Cruse 92-128 MARTIN P. SCHWADRON,Primary Examiner.

I. C. COHEN, Assistant Examiner.

1. IN COMBINATION WITH A BRAKE OPERATING BOOSTER, MEANS FOR OPERATINGSAID BOOSTER MECHANICALLY COMPRISING A HOUSING ATTACHED TO THE BOOSTER,MEANS THEREIN INCLUDING AN OPERATING CONNECTION TO SAID BOOSTER TOOPERATE THE LATTER UPON FAILURE OF THE NORMAL OPERATING MEANS THEREFOR,SAID LAST MENTIONED MEANS INCLUDING A GENERALLY FLAT, IMPERFORATEFLEXIBLE DIAPHRAGM, POWERFUL COIL SPRING MEANS HAVING ONE END SEATEDAGAINST THE INTERIOR WALL OF SAID HOUSING AND A BEARING PLATE FLOATINGLYSUPPORTED AGAINST THE DIAPHRAGM BY SAID SPRING MEANS, SAID BEARING PLATEBEING CONSTRUCTED AND DEFINED WITH TEMPORARY HOLDING MEANS FOR ACCEPTINGA SPRING LOCKOUT TOOL WHEN SUBSTANTIALLY ALIGNED WITH THE AXIS OF THESPRING AND FACING TOWARD THE HOUSING WALL SEATING SAID SPRING END, SAIDHOUSING HAVING AN OPENING ALIGNED WITH THE AXIS OF SAID SPRING AND THETEMPORARY HOLDING MEANS FOR THE BEARING PLATE, A SPRING LOCKOUT TOOL FOREXTENDING THROUGH SAID OPENING FOR ENGAGEMENT WITH THE TEMPORARY HOLDINGMEANS TO ALLOW THE LOCKOUT TOOL TO BE OPERATED FOR COMPRESSING THELOCKING OUT THE SPRING MECHANICALLY WHEN THE SPRING IS EITHER IN ACOMPRESSED OR AN EXPANDED CONDITION, A REMOVABLE CAP FOR SAID HOUSINGOPENING TO SAEL OFF THE INTERIOR OF THE HOUSING WHEN THE LOCKOUT TOOL ISDISENGAGED FROM THE TEMPORARY HOLDING MEANS AND WITHDRAWN FROM THEHOUSING, SAID LOCKOUT TOOL COMPRISING A THREADED SHANK INSERTABLETHROUGH SAID HOUSING OPENING AND HAVING ONE END THEREOF CONSTRUCTED ANDDEFINED TO DETACHABLY INTERLOCK WITH THE TEMPORARY HOLDING MEANS, SAIDTHREADED SHANK HAVING NUT MEANS ON ITS OTHER END ENGAGEABLE WITH THEEXTERIOR OF SAID HOUSING AND COOPERATING THEREWITH AS THE NUT MEANS ISTIGHTENED TO COMPRESS SAID SPRING, SAID HOUSING IS PROVIDED WITH A TOOLSTORAGE POCKET FOR RECEIVING AND STORING THE MAJOR PORTION OF THELOCKOUT TOOL FOR PROTECTING SAME FROM ITS ENVIROMENT TO THEREBY MAINTAINTHE TOOL IN A CONVENIENT AND READILY ACCESSIBLE LOCATION IN A USEABLECONDITION WHEN THE SPRING IS REQUIRED TO BE LOCKED OUT, SAID TOOL BEINGTIGHTLY SECURED TO THE POCKET TO PREVENT LOSS OF SAME DURING OPERATIONOF THE ASSOCIATED VEHICLE BY THE NUT BEING TIGHTENED TO THE POCKET ANDRELEASED FROM THE POCKET BY UNTIGHTENING THE NUT AND WITHDRAWING THETOOL FROM THE POCKET.